Hydraulic locking device for braking, adjusting, and other purposes.



G. DUFFING.

HYDRAULIC LOCKING DEVICE 'F011 BRAK|NG,AD1UST|NG, AND OTHER PURPOSES.

APPLICATION F |LED MAR. 17, i910. 1 l 1,178,996, Patented Apr. 11,1916.

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' To all whom t may concern.'

UNITED srafrEs-rnTENr orribili I GEORG DUEEING, oriVILI-iEIM-oN-THE-EHINE, GERMANY.

HYDRAULIC LOCKING DEVICE ron. BEAKING, ADJUSTING, AND oTI-IEErUErosi-is.

Be it known-that I, GEORG DUFFING, of Illiilheim-on-the-Rhine, Germany,have invented certain new and useful Improvements in Hydraulic LockingDevices for Braking, Adjusting, and other Purposes, of

Awhich the following is a specification. e

This invention relates to locking or adjusting devices. Y

The ordinary forms of' adjusting and locking devices now employedusually consist of a piston located in a vhydraulic cylinder, in whichall the free space inthe cylinder is completely filled with liquid, sothat under certain conditions the piston is absolutely locked againstmotion in either di` rection. Such an apparatus must be so arianged'thatthe amount of liquid locatedL in the free space on one side of thepistonl is exactly equal to the amount ofliquid located-on the otherside, when the pistony is in its'intermediate position. Thisnecessitates a piston rod, or its equivalent, which extends through bothends of the cylinder, and also necessitates two stuiing boxes for thepiston rod. In the ordinary devices em.- ployed, it is absolutelyessential to keep the stuffing boxes tight, since a leakage of liquidfrom the free space detrimentally effects the operation of thedevice.

An object of my invention'isto produce* an adjusting and locking device,in which the piston rod of the operating piston eX- tends through oneend only of the hydraulic cylinder, andv in whichthe stuffing boxes arenot essential. y

A further object is to produce a l device of the character described, inwhich means are employed for simplifying and perfecting the operation ofthe'device. v

A further object is to "produce a device in which means are employed forautomatically maintaining the necessary 'quantity of liquid in the freespace of ythe hydraulic cylinder. v i Q 'f These, and other 4objects,-Iattain in a d evice embodying' the features herein described, andillustrated in the drawingsaccompanying and forming. a part of this 'apfplication In the drawings, Figure 1 is a sectionalview of aconstructional or Vdiagrammatic arrangement of a device embodying myinvention. FigfQ is a sectional view and discloses a less diagrammaticarrangement of a device embodying theprinciple diepere.;

Specicatonof Letters Patent. l Patented ADL 11, 191@ Applicationfiled-March 1'?, 1910. 4Serial No. 549,901.

een of the' deviceiiiuaraedin Eig. i. Eig.

'3 is a sectional view of apreferred form of' 'apparatus which embodiesmy invention; and Fig. 4 is a sectional view of a modified form of theapparatus shown in Fig. 3.

' In Fig. l, I have shown a simpleform of apparatus embodyingmycinvention, which is capable of being rigidly' locked -against motionin eitherl or both directions, and is capable of permitting motion inone direction and ofbeing rigidly locked against motion in the otherdirection. The device consists of a` cylinder a closed at one end,

a hollow piston b located in thecylinder a and provided ywith a hollowpiston rod o, the' interior ofl which communicates with the interior ofthe piston. The rod 0"' projects upwardly through an opening a formed inone 'endofgthe cylinder a and'itsl interior communicates with anequalizing receptacle or chamber va through ports m. The chamber asurrounds the rod c and is illustrated as being integrally formed with acollar or-fiange formed on the cylinder a aroundl the opening a. Thereceptacle n is adapted to beiilled with any suitable liquid, such asoil. and performsthe function vof an equalizing spaceforthe free' spaceon each Side of the pistonb within the cylinder a. With such anarrangement, it is not necessary "to provide a stuing boX for the rod'0, since any leakage fromy the cylinderv a will-.be received by the.ychamber n; It is',

however, essentialthat'the fit between'the rod Vand the opening afbe asc lose'as possible, so that the leakage will be' reduced to a minimum. Yv

In the vdevice illustrated, the upper end of the chamber a is shownopen.' In devicesy adapted to operate in ya horizontal position,

itis necessary to: close the open end of the chamber n by means of astufiing box or suitable packing gland. It will be apparent, however,that such an arrangement does not introduce thedifficulties encounteredwith.

devices of this character ordinarily employed, since pressure in thechamber fa is approximately equal to atmospheric pressure, and there isvery'little tendency for the liquid to leakpast` the stuffing box orgland.

Ports are provided in each side of the piston' and forma means ofcommunication between the free spaces inthe cylinder, above and belowthe piston, and the interior of the Piston' These Ports are' provided.with non-return valves d, lthe operation of which may be controlled by across-head g located in the piston and provided with an actuating rod f,which extends upwardly through the hollow piston rod and projects beyondit. The cross-head g is located between the stems of the valves l and iscapable of being moved upwardly to open the upper valve ci,

and downwardly to open the lower valve cl. rIlhe cylinder t may bestationary, and-in the device illustrated, it is assumed to bestationary. The rod c is adapted to be connected at one end to anapparatus or an agent, which tends to move the piston either up or down,or which alternately tends tok move it up and down; and the deviceillustrated is adapted to control the movements of the apparatusor agentconnected to the rod c.

The device operates in the following manner Let it be supposed that therod c is connected to an actuating agent, which tends to alternatelyraise and lower the piston and that it is desired to have the actuatingAY the influence of an upward force, but remains locked against downwardmotion by the practically incompressible liquid in the free space of thecylinder below the piston. When the piston moves upwardly in response toan 'upward force, transmitted to it by the agent or apparatus connectedto the upper endfoi the rod c, a flow of liquid from the space above thepiston into the interior of the piston takesplace through the upperport.v The upward motion of the cylinder causes the lower valve d toopen and permits of a iow of liquid from the interior of the cylinder tothe free space belo-w the cylinder. The liquid ejected from the freespace above the piston is not suflicient to Iill the increasing freespace below the piston, and, consequently liquid from the equalizingchamber n is drawn into the cylinder through the ports fm, and isdelivered, past the lower valve cl, to the free space below the piston.If, during the upward motion of the piston, the actuating force on therod c is reversed, the lower valve l will be immediately closed, by areversal of the ow of liquid through the port it controls, and willpreventv a downward'motion of the piston I), since it will coniine theliquid in the free spa-ce below the piston, After the piston has risenthe determined amount, the upper valve Z will be automatically closed,since its valve stem will be raised ofi vof the cross-head q. This willlock the piston against further upward motion, since the liquid in thefree space above it is confined.

If it is desired to permit a downward motion of the piston, thecross-head g is moved downwardly to open the lower valve d, so that theliquid below the piston may be discharged into the interior of thepiston. The downward motion of the piston will cause the upper valve (Zto open and will also cause liquid to enter the free space above thepiston, through the port controlled by that valve. The liquid dischargedfrom the free space below the cylinder is more than is necessary to fillthe increased free space above the piston; consequently, the excessliquid is delivered to the chamber e, within the rod c, or to thechamber a, through the ports m.

In the constructional form shown in Fig. 2, the hollow piston rod cagain forms the equalizing space e, which is in constant communicationwith the interior of the piston l). In this case, however, theequa-lizingv space e is capable of communicating with the free space inthe cylinder above and below the piston Z), not only through the valvesZ but also through the passages z' controlled by the slides 7L on therod f. In this construction, if the adjusting rod f is moved it doesnot, as in the previous example, positively open certain of the valvesd, but it is provided with cylindrical slides 71, snugly guided in thehollow piston rod c and adapted to open or to close the passages z'leading to both cylinder-chambers. For instance, on moving the adjustingrod f in the downward direction so as to open the lower passages v whileclosing the upper passages z', the locking or braking piston is free tofollow the downward movement, as the liquid driven from the free spacein ,thek cylinder below the piston escapes in the direction of thearrows 7c and Z as shown, partly into the free space in the chamberabove the piston and partly into the equalizing space e. If theadjusting rod f is raised, the upper passages z' are opened andthe lowerpassages i are closed. The piston Z) is then free to follow the upwardmovement and the liquid driven from the free space above the pistonenters the free space below the piston, and an auxiliary supply ofliquid is also delivered to the free space below the piston from theequalizing space c.

In the constructions shown in `Figs. l and 2 the equalizing tank orspace e is in constant communication, for instance, through ports m inthe hollow piston rod c, with a receptacle n which receives any liquidthat may escape therein owing,Vr for instance, to leakages between the`piston rod and its guide. Such liquid thus flows back into theequalizing tank and from the latter again passes into the braking orlocking cylinder a.

Consequently no absolutely tight stuffing lli) boxes need be provided onthe piston rod guide. As already stated, the arrangement of theequalizing tank e may be used also in connection with all kinds -ofhydraulic brakes.

A further constructional form is shown in Fig.- 3. lIn this case thevalves d arranged within the hollow piston b are atx-- ially movablealong the surface of-a slide h and are provided with controlling edges ocooperating with` thosegon the slide fh.

The common valve seat is constructed iny the forni ofa simple ring pheld in place by a screwed-in piston coveror end 'w and against whichthel valves d are pressed by. springs g. The slide h. forms part of theadjusting rod f', and is provided with recesses 1 for the passage of thelocking liquid.

The equalizingtank e subjected, for in stance, to atmospheric pressure,is inv constant communication with the spaces??7 located between the twovalves through passages fm, and s, Vas well as through passages t" meansof its controlling edges 0 will create a free passage forthe liquid. Thelocking follow the upward piston b is thus 'free' to movementv and theliquiddisplaced thereby from the upper cylinder-chamber 'escapes throughthe passage between the upper con trolling edges o and through the lowervalve d intoY the lower cylinder-chamber, the required e for equalizingquantity of liquid purposes being supplied fromthe equalizing tank e(Theniore the piston approachesits new position of rest, the more thecontrolling edges o are closed. The reverse is the case if theVadjusting rod f and theI slide, It are moved in the constructional formaccording to Fig. j 3, provision moreover is made ofrelastic inter- Ymediate members, such as for instance pres-A sure springs v interposedbetween the `ad-,. justing rod and the locking piston and its rod orextension. These elastic intermediate members have the tendency toconstantly maintain the adjusting slide h in its central positionwithinthe locking piston and to render the speed of adjustment dependentin a favorable manner on the force acting on the slide ro'd,'for it willbe seen that on the force of adjustment increasing, the free crosssection for the passage of the lockingv liquid is simultaneouslyVincreased so that from both causes the piston moves in a more rapidmanner. f Y

is in communication the cylinder above through the'` ports u;

l to an y. upward fforce.

downward direction. In the can supply.

always in communication with the interior' t represents aconstructionalform of the invention in which the adjusting slidelz,2 isguided within the hollow :locking piston-2')2 so as to be completely`relieved of locking liquid pressure. The slide 'h2 is in effect ahollow piston valve and is provided with an upper and lowerv series of'ports 02, eachof which communicates with. the interiorl of the valve andis respectively controlled bythe upper and lower valves d2. Each valved2 is annular and surrounds the slide or piston valve h2, and is held toits seat on the ring p2 by the coiledV spring q2. An annular ange m2 isprovided on the inner face of each end of lthe piston b2 and theseflanges coperate with the'valves. (Z2 informing an inclosing cage forthe slideor piston valve h2. Y located between the valves cl2',y whenthe slide h2 is in the normalY or intermediate position, and the flow ofliquid thro-ugh them is controlled b thevalvesdZ.v The hollow piston rodcgis constructed so as to forni the equalizing tank e2, or it mayterminate upwardly in an equalizing tank or.

space, yif desired. As in the previous case, pressure springs o2 areinterposed'between Vthe slide h2 and the locking piston vZ22 to causethe slide to always maintainits central position when the adjustingrod-isffree. `llhenthe adjusting rod f2 is moved upvwardly,` the upperseries of ports 02 are raisedabove the upper edges of the valves Aseriesof ports y2 are'V (l2. This places the interior of the slide h2'in communication withthe free space inthe cylinder a2, above the pistonb2, and permits the piston b2 to move upwardly in response During theupward motion ofthe piston, liquid enters its interior from the freespaces in the upper portion of the cylinderaf", through vthe ports u2,and passesthroughfthe upper series of portsf02, throughthe interior ofthe slide h2,

through the ports l1/2, past thelower valvesl d?, and out through-the:lower ports u2 into the freeV space; injthe cylinder belowpthe piston'62. Thel preponderance of liquid pressurek above the lower valve d?over the liquid pressure below the valvev issufcient to openthe valveagainst, the force vof its closing. spring, during this upward motiono-f the piston, and an Aauxiliary supply of liquid will be deliveredfrointhe space e2 into the :free space below the piston, to supply theexcess demand for liquid beyond that which the free space above' thepiston The equalizing space e2 of the slide 71.2. ywardly, in responsecarries with it the upper valve (Z2, and consequently moves .the valveto close the upper ports 02. y piston 52 is `again locked against Asthek piston b2 moves up- 'to the upward force, it.

roo

ica

Whenthe yports, 02 are closed, .the j motion.

"When therodf2 is moved downwardlyto 18e .l der, a hollow piston openthe lower series of ports o2, the piston b2 is capable of being moveddownwardly, and liquid is discharged from the freespace below the pistoninto the free space above the piston, and also into the equalizingspacey cf. During this motion of the piston b2, the upper valve Z2 isautomatically openedy by the preponderance of liquid pressureV below it.

In any of the cases hereinbefore described, the liquid of the equalizingtank may be supplied either at atmospheric pressure or, if desired,under high or low pressure, as will be easily understood.

I claim:

l. A hydraulic braking device, comprising a cylinder, a piston mountedfor movement within the cylinder and having valved passages formedtherein and communicating with the free spaces at the ends of thecylinder, van equali'zing space for delivering liquid to or receivingliquid from the passages of said piston during relative motion betweenthe piston and the cylinder', and means mova'bly mounted within thepiston for controlling the operation of the valves of said passages.

2. A. hydraulic braking device, comprising a. cylinder, a piston mountedfor movement within the cylinder and' having passages formed thereincommunicatingf with tghe free ends of the cylinder, an equalizing spacecommunicating with the piston passages and formed within the piston rod,valves for controlling the delivery of fluid through the pistonpassages, and means slidably mounted within the piston and movablerelative thereto for controlling` the operation of said valves.

3. In a hydraulic braking device, a cylinmovable with relation to thecylinder and so located therein as to confine Vin opposite ends of the'cylinder bodies of liquid which take no part in the act of moving thepiston, passages formed in the piston for transferring liquid from oneof the bodies to the other,v an equalizing space communicating with saidpassages for delivering liquid thereto or for receiving liquid therefromduring relative motion between the piston and the cylinder, valves forcontrolling said passages, and means movable with relation to both thepiston and the cylinder for controlling the operation of said valves.

4. A hydraulic braking` device, comprising a cylinder, a. piston mountedfor movement within the cylinder, and having passages formed therein andcommunicating with the free spaces at each end of the cylinder, a hollowpiston rod for said piston with its interior passage in communicationwith said piston passages, oppositely disposed valves for controllingthedelivery of liquidv .trom and to the free spaces of thecylinderthrough the piston passages, an equalizing space communicating with theinterior of the piston rod, kand means for controlling the operation ofthe valves and communication between said equalizing space and the freespaces of the cylinder.

5. In a hydraulic braking device, a cylinder, a hollow piston locatedwithin the cylinder movable with relation thereto and provided withvalved passages communicating with the interior of the cylinder and withan equalizing space located within the piston rod of said piston, valvesfor said passages, an adjusting' rod located within the hollow pistonrod and a crosshead mounted on the adjusting rod and located within thepiston for opening said valves.`

6. A hydraulic braking device, comprising a cylinder, a piston'mountedwithin and movable relative of the cylinder and having passages formedtherein communicating with each free space of the cylinder and with apassage provided through the piston rod, an` equalizing spacecommunicating with said piston passages through the piston rod,oppositely disposed pressure responsive valves for controlling thedelivery oi' liquid through the piston passages, valve means slidablymounted within the piston for controlling the operation of said valvesand for controlling communication between said passages and said spaces,and means extending through the piston rod for actuating said valvemeans. l

7. In a hydraulic locking or braking device, a cylinder, a hollow pistonlocated in said cylinder and' provided with an equalizing space, andpassages extending through the wall of the piston and communicating withthe interior of thevpiston and the free space in the cylinder above andbelow the piston, valves controlling said passages and meansreciprocable within said piston and relatively thereto for actuatingsaid valve.

8. In a hydraulic locking or braking device, the combination with anequalizing receptacle, of a cylinder, a hollow locking or braking pistonlocated in said cylinder and provided with passages connecting theinterior of the piston with the free space in the cylinder, valveslocated in saidv piston, an adjusting rod, and a slide mounted onsaidrod and provided with passages located between the slide and said valvesfor the passage of liquid between the equalizing receptacle and thepiston. 1

9. In a hydraulic locking or braking device, the combination with anequalizing receptacle, a cylinder, a hollow piston provided withpassages connecting the interior ofthe piston with the free spaces ofthe cylinder, a piston Vrod secured to the piston and provided with aninterior passage, communicating with the interior of the piston and saidreceptacle, valves controlling the passages in the the valves, valvesand on which the valvesjare guided, and an adjusting rod on which saidslide is mounted. v

10. In a hydraulic locking or braking device the combination with anequalizing receptacle of a hollow locking or braking piston, Valvescontrolling the passage of the liquid between the equalizing receptacleand hollow piston, a slide coperating with said valves and slidablerelatively to said piston, and means Vfor yieldingly supporting `thesaid slide and tending to hold the same in piston, a slide coperatingwithV said central position within the piston, substantially as setforth.

' 11, In a hydraulic locking or braking device the combination with anequalizing receptacle, of a hollow locking or braking piston, valvescontrolling the passage of liquid between the equalizing receptacle andhollow piston, a slide coperating with said valves and springsinterposed between` the Copies of this patent may be obtained for avalve seat common toy axially 'trolling the passagesl iive cents each,"oy addressing the Washington, D. G.

said slide and the walls of the piston, an ada justing rod for operatingsaid slide, a tubular guide for said adjusting rod, and springsinterposed between the adjusting rod and the said tubular guidesubstantially as and for the purpose set forth.. l

j 12. In a hydraulic locking or braking de-` vice, ythe combination withan equalizingreceptacle ofa hollow piston communicating with saidequalizing receptacle, Valves confor the liquid between said piston andreceptacle, springs for yieldingly supporting said Valves, a slidecoperating with said valves and springs interosed vbetween both Jfacesand the adjacent walls of the piston, all substantially as described. j

In testimony whereof I aiix lmy signatureY in presence oftwo witnesses.1 i GEORG DUFFING.

Witnesses:

Louis VANDORY, Bnssm F. DUNLAP.

Commissioner of I Eatents,

of the said slide-

